Multi-functional printers (multi-functional peripherals), which are also known as MFPs, and all-in-one printers (AIO) provide a plurality of functions, such as a printer function, a scanner function, and a copy function. Efforts are continually being made to expand the number of features for such devices, while at the same time maintaining quality and reducing their cost.
One such feature is collation, where multiple copies of a single document are printed out in the document's page order. For collation, the printed sheets eject in order from the first page of the document to the last page for the first full copy, and then from the first page to the last page again for the second full copy, etc., repeating the process each time for every full copy requested by the user.
From the above description of collation, it can be appreciated that each page is loaded into printer storage as it arrives, and will remain in printer storage until the last copy of the page has ejected. As a result of the printing order for collation this also means that after all pages have arrived, then all pages are held in storage at the same time when multiple full copies are requested. Thus, storage must be large enough to hold all pages of a job to support collation. But for certain jobs requiring collation, such as copy jobs, the pages can be quite large and the printer's internal memory may not be large enough to support collation, even when data compression techniques are used.
Because of storage limitations, collation is not always possible for all jobs without installing dedicated storage hardware such as an internal hard disk. But since adding additional internal storage increases the overall cost of the printer, it is desirable to find a low-cost solution which supports full collation without adding additional internal storage. The solution proposed here takes advantage of the fact that existing storage needed for collation is often available externally, such as through a network, rather than internally as part of the printer hardware. Since using existing external storage provides the storage needed for collation without incurring any additional hardware costs for internal hard drives, it is an ideal solution for providing full collation support while minimizing overall printer cost.
It is useful to note that external storage may also be used by printers for other purposes and during other processes than the collation process. For example, storage is required for certain jobs such as PDF and XPS printing because they require all job data to arrive first and be fully placed into storage before page rendering can begin, regardless of whether copy or collation processing is requested.
To hold these types of incoming jobs, a printer's internal memory also may not provide enough storage and so external storage may be used to increase the amount of storage available beyond that provided by the printer's internal memory. However, the application of external storage listed for the PDF/XPS example above and in the general case stands in contrast to the idea proposed here which is to use external storage to store the image data which is input to the collation process.
In summary for the collation feature, many low-cost printers including all-in-ones (AIO) and multi-functional peripherals (MFP) cannot provide the full collation feature for large jobs without the additional cost of an internal hard disk or additional internal memory and storage. Accordingly, it would be desirable to have an image forming apparatus in the form of a multi-functional peripheral (MFP) or all-in-one (AIO) unit that can leverage external storage units or systems to provide the image forming apparatus with full collation capabilities when copy collation is requested within the job data.